1. Field of the Invention
The present invention relates to an operating process for the formation of a steady particle stream of particles which are conveyed within a flow conduit through the intermediary of a flow medium, and which are introduced into the medium flow under the effect of gravity through an infeed conduit discharging into the flow conduit; as well as to an arrangement for the effectuation of the process.
2. Discussion of the Prior Art
The conveyance of particles through the intermediary of a flow medium is known. For solid particles there are utilized gaseous or liquid flow media. For example, in the production of ceramic nuclear fuel particles, the gel particles which are produced from hydrobrine or aqueous salt solutions containing the nuclear fuels, are applied through trickling onto a drying web by means of wash water as the flow medium, having reference to "Transactions of the American Nuclear Society", 1977, Vol. 27, pgs. 292-293. Serving for the application of the gel particles is a particle discharge member which is pivotable transversely relative to the drying web, having reference to Berichte der Kerforschungsanlage Julich, Jul-1258, 1975, pg. 116. In order to achieve a quality of nuclear fuel particles which is adequate to the demands set thereon, it is necessary that the particle deposition on the drying web be rendered uniform. Aimed for is a separation of the particles on the drying web or a definite multi-layered particle deposition. In order to achieve the foregoing it is necessary that the particle stream in the flow conduit be correlated over each unit of time with the drying web surface which is to be covered with the particles.
It is also known that the particle flow can be regulated through the interposition of a shut off device in the infeed conduit. Nevertheless, particularly during the starting up of the apparatus as well as at a low fill level of the particle supply container, is it impossible to avoid disruptions in the particle stream. Discontinuities will also be encountered in that gas bubbles in the flow medium lead to the formation of larger gas bubbles in the region of the shut off device, as well as at the discharge of the infeed conduit into the flow conduit, which can disrupt or even completely block the particle passage. The added introduction of flow medium into the particle supply container and the setting of an excess pressure with respect to the pressure reigning in the flow conduit cannot eliminate the encountered disruptions in a satisfactory manner.